1. Field of Invention
This invention relates to cardiac catheters, more particularly, this invention relates to a steerable catheter with a precurved tip portion designed for use in the coronary sinus of a human heart.
2. Prior Art
Catheters have been in use in medical procedures for many years. For example, they can be used to convey an electric stimulus to a selected location within the human body. Further, they can be used to monitor and make measurements for diagnostic tests of activities within the human body. Such catheters examine, diagnose and treat while positioned at a specific location inside the human body which is otherwise inaccessible without more invasive procedures. Recently, catheters have become more commonly used within the human heart and vascular system. In such use, the catheter is first inserted into a major vein or artery which is near the body surface and is then guided to the area for diagnosis or treatment by manipulating the catheter through the vessels of the body. As the utilization of catheters in remote and difficult to reach portions of the body including the heart has increased, it has become important to control precisely the movement of the catheter and its placement within the heart.
Control of the movement and placement of a catheter is difficult because of the inherent structure of the catheter. The body of conventional catheters is long and tubular. To provide sufficient control over the movement of the catheter, it is necessary that its structure be somewhat rigid. However, the catheters must not be so rigid as to prevent navigation of the catheter through the body vessel to arrive at the precise location where the medical procedure will be performed. In addition, it is important that the catheter not be so rigid as to cause damage to the body vessel through which it is being passed.
While it is important that the catheter not be so rigid as to cause injury to vessels and arteries, it is also important that there is sufficient rigidity in the catheter to accommodate torque control, i.e., the ability to transmit a twisting force along the length of the catheter. Sufficient torque control enables controlled maneuverability of the catheter by the application of a twisting force at the proximal end of the catheter that is transmitted along the catheter to its distal end. The requirement that existing catheters provide greater torque control often conflicts with the need for reduced rigidity to prevent injury.
As above stated, catheters are used increasingly for medical procedures involving the human heart. In these procedures, the catheter being used is typically guided to the heart through vessels including arteries, veins, and cardiac chambers and then it is placed at a precise location within the heart. Typically, the catheter is inserted in an artery or vein in the leg, neck, upper chest or arm of the patient and threaded, often with the aid of a guidewire, through various arteries and veins until the tip of the catheter reaches the desired location.
The distal portion of the catheter may be preformed into a desired curvature so that by torquing the catheter about its longitudinal axis, the catheter can be manipulated to the desired location within the heart. For example, U.S. Pat. No. 4,882,777 discloses a catheter with a complex curve at its distal end for specific procedures in the right ventricle of a human heart. In addition, there have been a number of catheters with a specialized curvature at its distal end designed for use in the coronary sinus, including U.S. Pat. Nos. 5,423,772, 5,549,581, 5,643,231, and 5,722,963.
While these catheters are particularly useful in the coronary sinus, each catheter is designed to be used for either a superior or an inferior approach to the coronary sinus, but not for both. In addition, the approach to the coronary sinus in some hearts is difficult because of the unusual anatomy of individual hearts. Further, entry into the coronary sinus is made more difficult because the right atrium of the heart is beating during the medical procedure.
To increase the ability of catheters to move and navigate within a human body, steerable catheters containing deflectable portions have been designed. Because these steerable catheters are deflectable, they can be used for medical procedures which require precise control over the orientation of the catheter tip, as shown, for example, in U.S. Pat. No. 5,728,828. With the devices disclosed in this patent, deflection of the catheter body is achieved by increasing or decreasing the axial compressive force on one side of the steerable tip by applying tension to, or removing tension from, the pull wire. By increasing the compressive force to one side of the tip, it is deflected in a predetermined direction.
U.S. Pat. No. 5,779,669 discloses a steerable catheter which includes a complexly curved section located proximal from the distal tip, designated by element 48 in FIG. 2. This complexly shaped steerable catheter is designed for utilization within the right atrium of the heart for ablation procedures against the outer wall of the right atrium, as shown, for example, in FIG. 8.
To control the movement of the distal portion of these catheters, control handles have been attached at the proximal end of the catheter body. For example, U.S. Pat. No. 5,395,329 describes a device useful for controlling the movement of steerable catheters. However, none of these steerable catheters have been specifically designed for usage in the coronary sinus and none in particular for usage for an inferior approach to the coronary sinus.
Accordingly, it is an object of this invention to prepare a steerable catheter designed for ease of access into the coronary sinus.
Another object of this invention is a steerable catheter for use in the coronary sinus which contains a fixed curve at its distal end.
Another object of the invention is a steerable catheter for use in the coronary sinus which contains a fixed curve at its distal end which curve is curved out of a plane formed by the remainder of the steerable catheter.
Another object of the invention is a steerable coronary sinus catheter which can perform electrophysiological sensing procedures from various locations within the coronary sinus.
It is a still further object of this invention to provide a fixed shape, steerable coronary sinus catheter which can sense electrical activity in and/or deliver electrical energy to the right and left atria as well as the left ventricle.
It is a still further object of this invention to provide a fixed shape steerable coronary sinus catheter which can approach the coronary sinus using either a superior or inferior approach.
These and other objects are obtained by the design of the steerable coronary sinus catheter of the instant invention.
The present invention is a steerable catheter specifically designed for use in the coronary sinus of the human heart which includes a precurved, flexible catheter body having a proximal and distal end containing a lumen, and a steerable catheter handle secured to the proximal end of the catheter body, wherein the catheter body includes a generally straight proximal section, a deflectable distal section and a precurved tip portion. In a preferred embodiment the precurved tip portion is formed in the shape of a hook, sized and shaped for facilitating entry of the catheter into the ostium of the coronary sinus wherein the hook portion is preferably curved out of a plane formed by the remaining portion of the catheter. Preferably, this precurved tip portion extends through an arc from about 45 to about 90 degrees and is curved out of the plane of the remaining portion of the catheter at least about 10 degrees and preferably from about 20 degrees to about 50 degrees.
In a further preferred embodiment the deflectable distal section is deflectable through an arc from about xe2x88x9215 degrees to about 180 degrees.
While the present catheter is designed for use in the coronary sinus, it is certainly not limited to that application but can be used for other procedures in the heart and in other locations within the body. Further, the catheter""s use is certainly not limited to electrophysiological diagnostic applications but can be used for interventional pacing, defibrillation, ablation, cardioversion and other such cardiac procedures.